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Department of Nutrition and Dietetics, The Children's Hospital Westmead, Sydney, AustraliaDepartment of Respiratory Medicine, The Children's Hospital Westmead, Sydney, Australia
This paper summarises the 2017 Nutrition guidelines for CF for Australia and NZ
•
A systematic approach to evidence appraisal and guideline development was used
•
Nutrition assessment, nutrition support and micronutrient supplementation are covered
•
Nutrition-related topics including CF-related co-morbidities and PERT are covered
•
Novel topic areas include genetic modulators, overweight/obesity and probiotics
Abstract
Optimal nutrition care is important in the management of cystic fibrosis (CF). This paper summarises the ‘2017 Nutrition Guidelines for Cystic Fibrosis in Australia and New Zealand (NZ)’. CF dietitians formulated 68 practice questions which were used to guide a systematic literature search and review of the evidence for nutrition in CF. Identified papers underwent quality and evidence assessment using the American Dietetic Association quality criteria checklist and the National Health and Medical Research Council of Australia (NHMRC) rankings. Evidence statements, graded recommendations and practice points were developed covering core nutrition topics (assessment and nutrition interventions including oral, enteral and micronutrient supplementation); nutrition-related co-morbidities (including pancreatic insufficiency, CF-related diabetes, bone health and distal intestinal obstruction syndrome); and key new topic areas (genetic modulator therapies, overweight/obesity and complementary therapies). This paper showcases highlights from the guidelines, focussing on new topic areas and geographic and climate considerations for vitamin D, salt and hydration.
]. Despite these improvements, nutritional deficits are still prevalent in CF, and can occur at a young age, persist throughout life, normalise with intervention, or emerge episodically [
]. The aetiology of undernutrition in CF is multifactorial, resulting from a combination of increased energy expenditure, nutrient malabsorption, increased energy losses and inadequate dietary intake [
]. The use of clinical practice guidelines has been advocated as a strategy to improve the quality of health care by facilitating the application of consistent, evidence-based care [
Evidence-based practice recommendations for nutrition-related management of children and adults with cystic fibrosis and pancreatic insufficiency: results of a systematic review.
The ‘Nutrition Guidelines for Cystic Fibrosis in Australia and NZ’ were released under the custodianship of the Thoracic Society of Australia and New Zealand (TSANZ) in August 2017, as a planned update of a previously published clinical practice guideline [
]. Australia and NZ are diverse countries with a CF population of approximately 4000 individuals, with dramatic climate variance ranging from tropical, hot and dry, through to cool temperate conditions [
]. Guidelines specific to the Australian and NZ context were considered salient as many aspects of nutrition management are affected by geographical and climatic conditions, including salt supplementation, hydration and vitamin D.
The purpose of this paper is to showcase updated or changed recommendations for core components of nutrition care, along with highlights from the guideline recommendations and practice points. This paper highlights topic areas that are new, unique, or impacted by climatic considerations. The guidelines promote an interdisciplinary approach to management of nutrition in CF. Many of the guideline recommendations will have relevance to those living in or travelling to other regions, including those with similar climates, for example south-eastern Europe, Asia, Africa and parts of South America.
2. Methods
The full methodology used to develop the ‘2017 Nutrition Guidelines for Cystic Fibrosis in Australia and NZ’ is provided elsewhere [
Providing the evidence for the 2017 nutrition guidelines for Cystic Fibrosis in Australia and New Zealand: Techincal report. Thoracic Society of Australia and New Zealand.
A working group was formed comprising over 40 Australian and NZ CF dietitians. Expressions of interest (EOI) were circulated via the Dietitians Association of Australia and Dietitians New Zealand. Roles of the dietitian working group included:
•
Project chairs and facilitators - overarching responsibility for the planning and execution of the guideline development, coordination of chapter groups and compilation of the evidence base
•
Chapter leads – responsible for overseeing evidence appraisal and development of evidence statements and practice recommendations for their allocated chapter
•
Chapter group members - provided input into the development of clinical questions and appraised research papers for quality and evidence level
•
Methodological experts - PhD qualified dietitians provided support and direction regarding literature review processes, writing evidence statements, and grading of practice recommendations
An interdisciplinary expert group, recruited via EOIs through the TSANZ, Cystic Fibrosis Australia and Cystic Fibrosis New Zealand, was formed to provide specific context expertise. This group was comprised of respiratory physicians and other medical specialties related to CF care including allied health professionals, nurse specialists, a consumer and a medical librarian.
2.2 Development of practice questions
The dietitian working group identified and drafted the practice questions in PICO (Population, Intervention, Comparator, Outcome) format. The questions covered all aspects of the nutrition care process including nutrition assessment and diagnosis, intervention, monitoring and evaluation and management of nutrition-related comorbidities. Further input and refinement was sought from the interdisciplinary expert group.
2.3 Data sources and search strategy
Systematic literature searches were conducted for each clinical question with medical librarian support. Electronic databases (Embase, CINAHL, PubMed, AustHealth, and Cochrane) were searched from January 2002 to June 2016. Key papers published between July 2016 and March 2017 were subsequently included if deemed to significantly influence practice or necessitate changes to recommendations or practice points.
Search terms were based on the Library of Medical Subject Headings (i.e., MESH terms) and always included the terms “cystic fibrosis”, “nutrition”, and “diet” (https://meshb.nlm.nih.gov/serarch).
2.4 Study selection
All literature search results underwent a two-stage screening process. Stage one included a review of titles and abstracts of all retrieved studies by a project chair, facilitator or chapter lead. All irrelevant, duplicate and non-English publications were removed and full text articles for the remaining studies were sourced. In stage two, chapter leads and group members excluded articles that did not address any PICO questions in that chapter.
2.5 Literature appraisal
Two chapter group members independently appraised each study for level of evidence and quality rating. Each paper was assigned a level of evidence using the NHMRC criteria rankings [
]. Where consensus regarding the level of evidence and/or quality rating was not reached between the two group members, a methodological expert was consulted to provide opinion. Consensus was reached through discussion.
2.6 Development of evidence statements, recommendations and practice points
For each PICO question, consideration was given to the volume of evidence, consistency of results and potential clinical impact. Generalisability and applicability of the recommendation to Australian and NZ healthcare contexts was also considered. The body of evidence was synthesised into evidence statements using the NHMRC evidence statement matrix [
]. Where sufficient evidence was available, practice recommendations were developed, and each was assigned a grade according to the NHMRC grade of recommendation definitions for evidence level: A (Excellent), B (Good), C (Satisfactory) or D (Poor) [
]. Where insufficient evidence was available, consensus-based practice points were developed by the dietitian working group with comments sought from the interdisciplinary expert group.
3. Results
The guidelines are organised into eighteen chapters (Table 1). Sixty-eight PICO questions were devised from which 41 graded recommendations and a series of practice points were developed. These are available in the guideline's Executive Summary https://www.thoracic.org.au/journal-publishing/command/download_file/id/44/filename/Preface.pdf. Most chapters include a narrative background section (aetiology), as well as information on nutrition assessment, intervention, monitoring and evaluation for that topic area. Since the previous guidelines [
], four new topic areas have been added including dietitian prescribing in NZ, overweight/obesity, nutritional implications of genetic modulator therapies, and complementary nutritional therapies including probiotics. All guideline chapters are freely available via the TSANZ website www.thoracic.org.au.
Table 1Outline of guideline chapters.
Guideline Chapters
1
Introduction
2
Methods
3
The Role of Nutrition in CF Care
4
Service Delivery
5
Nutrition Assessment
6
Nutrition Interventions 6.1 – Undernutrition
-
Behavioural Modification Strategies
-
Appetite Stimulants
-
Oral Nutrition Supplements
-
Enteral Feeding
-
Parenteral Nutrition
6.2 – Overweight and Obesity
7
Macronutrients
8
Fat Soluble Vitamins
9
Minerals
10
Pancreatic Enzyme Replacement Therapy
11
Gastrointestinal and Hepatobiliary Considerations 11.1 – Gastro-oesophageal Reflux Disease 11.2 – Distal Intestinal Obstruction Syndrome and Constipation 11.3 – Colon Cancer Screening 11.4 – Liver Considerations 11.5 – Additional Considerations and the Role of the Gastroenterologist
12
Cystic Fibrosis Related Diabetes
13
Bone Health
14
Special Considerations 14.1 – Pregnancy 14.2 – Genetic Modulator Therapies
Implementing, Evaluating and Maintaining the Guidelines
18
Evidence Matrices
Appendices -Dietitians Association of Australia Cystic Fibrosis Role Statement -Comparison of WHO and CDC growth chart weight for age measurements in children birth to 24 months
In New Zealand, Designated Dietitian Prescribers can prescribe subsidised items for therapeutic nutrition intervention, including fat-soluble vitamins, pancreatic enzyme replacement therapy, zinc, iron and high dose vitamin D, along with oral and enteral supplements. This promotes timely access to nutrition-related medications and contributes to improved patient care. This information in the guidelines may be useful for the development of extended scope of practice frameworks for dietitians.
3.2 Nutrition assessment
Nutrition assessment is a cornerstone component of CF interdisciplinary care, with dietitians playing a key role. For outpatients, nutrition surveillance is recommended at least four times a year, including a comprehensive nutrition assessment undertaken at least annually [
]. The guidelines recommend that inpatients undergo nutrition assessment within 48 h of admission and a minimum of once per week thereafter. Inpatient assessments should encompass acute changes in appetite, the possible impact of hospital menu foods and quantification of intake during inpatient stay compared to usual intake. The guidelines provide information to clinicians, including that which may be used to support business case development for adequate dietetic services, food service and nutrition support options.
Table 2 outlines the criteria for classifying height, weight and BMI status in CF. General population paediatric growth charts differ between countries, with Australia using the WHO growth charts for children 0–2 years [
Source: Saxby N, Painter C, Kench A, King S, Crowder T, van der Haak N, et al. Nutrition Guidelines for Cystic Fibrosis in Australia and New Zealand. Bell S, editor. Sydney: Thoracic Society of Australia and New Zealand; 2017.
WHO growth charts are used for all infants <2 years of age. For 2–18 years, at the time of writing, CDC growth charts are used in Australia, NZ-WHO growth charts are used in New Zealand (http://www.health.govt.nz/our-work/life-stages/child-health/well-child-tamariki-ora-services/growth-charts). The overweight and obesity cut-offs for children and adolescents are the same values used in each respective growth chart, reflecting the general population cut-offs in the absence of evidence to guide CF-specific thresholds.
WHO growth charts are used for all infants <2 years of age. For 2–18 years, at the time of writing, CDC growth charts are used in Australia, NZ-WHO growth charts are used in New Zealand (http://www.health.govt.nz/our-work/life-stages/child-health/well-child-tamariki-ora-services/growth-charts). The overweight and obesity cut-offs for children and adolescents are the same values used in each respective growth chart, reflecting the general population cut-offs in the absence of evidence to guide CF-specific thresholds.
WHO growth charts are used for all infants <2 years of age. For 2–18 years, at the time of writing, CDC growth charts are used in Australia, NZ-WHO growth charts are used in New Zealand (http://www.health.govt.nz/our-work/life-stages/child-health/well-child-tamariki-ora-services/growth-charts). The overweight and obesity cut-offs for children and adolescents are the same values used in each respective growth chart, reflecting the general population cut-offs in the absence of evidence to guide CF-specific thresholds.
OR BMI 50th to <91st percentile using NZ-WHO growth chart
WHO growth charts are used for all infants <2 years of age. For 2–18 years, at the time of writing, CDC growth charts are used in Australia, NZ-WHO growth charts are used in New Zealand (http://www.health.govt.nz/our-work/life-stages/child-health/well-child-tamariki-ora-services/growth-charts). The overweight and obesity cut-offs for children and adolescents are the same values used in each respective growth chart, reflecting the general population cut-offs in the absence of evidence to guide CF-specific thresholds.
Female BMI 22 to <27 kg/m2 Male BMI 23 to <27 kg/m2
Routine nutritional care and surveillance +/− education and preventative counselling
Acceptable
Weight-for-length 25th to <50th percentile AND weight & length tracking AND within 2 percentile bands of each other
BMI 25th to <50th percentile AND weight & height tracking along previous percentiles AND no recent weight loss
Female BMI 20 to <22 kg/m2 Male BMI 20 to <23 kg/m2 AND no unintentional recent weight loss
Routine nutritional care and surveillance +/− education and preventative counselling
Suboptimal – at risk of undernutrition
Weight-for-length 10th to <25th percentile AND/OR weight or length decreasing >1 percentile band AND/OR no weight gain
BMI 10th to <25th percentile AND/OR weight loss or plateau over 2–4 months
BMI <20 kg/m2 AND/OR ≥ 5% unintentional weight loss over 2 months
Persistent undernutrition refers to undernutrition that is non-responsive to previous recommended interventions over a period of monitoring and evaluation that is individually determined by the treating CF team.
Persistent weight for length < 10th percentile AND/OR weight falling >2 percentile bands with stunting of growth AND/OR failure of previous nutritional interventions to improve nutritional status
BMI <10th percentile AND/OR weight falling >2 percentile bands with stunting of growth AND/OR failure of previous nutritional interventions to improve nutritional status
BMI persistently <18.5 kg/m2 AND/OR ≥ 5% unintentional weight loss over 2 months despite previous nutritional interventions, regardless of starting BMI
As above, plus medical +/− psychological evaluation investigating factors contributing to undernutrition. Consider intensive nutritional support via enteral nutrition
While there are no evidence-based guidelines for treating overweight in infancy, recognition of rapid weight gain might identify if interventions to ameliorate the rate of weight gain are indicated (Centers for Disease Control, https://www.cdc.gov/mmwr/pdf/rr/rr5909.pdf). Important to distinguish between catch-up growth after early deficit, and rapid weight gain risking overweight or obesity in childhood.
Use growth chart to identify rapid weight gain.
Overweight: BMI 85th to <95th percentile using CDC growth chart (Australia)
WHO growth charts are used for all infants <2 years of age. For 2–18 years, at the time of writing, CDC growth charts are used in Australia, NZ-WHO growth charts are used in New Zealand (http://www.health.govt.nz/our-work/life-stages/child-health/well-child-tamariki-ora-services/growth-charts). The overweight and obesity cut-offs for children and adolescents are the same values used in each respective growth chart, reflecting the general population cut-offs in the absence of evidence to guide CF-specific thresholds.
OR BMI 91st to <98th percentile using NZ-WHO growth chart
WHO growth charts are used for all infants <2 years of age. For 2–18 years, at the time of writing, CDC growth charts are used in Australia, NZ-WHO growth charts are used in New Zealand (http://www.health.govt.nz/our-work/life-stages/child-health/well-child-tamariki-ora-services/growth-charts). The overweight and obesity cut-offs for children and adolescents are the same values used in each respective growth chart, reflecting the general population cut-offs in the absence of evidence to guide CF-specific thresholds.
Obese: BMI ≥95th percentile using CDC growth chart (Australia)
WHO growth charts are used for all infants <2 years of age. For 2–18 years, at the time of writing, CDC growth charts are used in Australia, NZ-WHO growth charts are used in New Zealand (http://www.health.govt.nz/our-work/life-stages/child-health/well-child-tamariki-ora-services/growth-charts). The overweight and obesity cut-offs for children and adolescents are the same values used in each respective growth chart, reflecting the general population cut-offs in the absence of evidence to guide CF-specific thresholds.
WHO growth charts are used for all infants <2 years of age. For 2–18 years, at the time of writing, CDC growth charts are used in Australia, NZ-WHO growth charts are used in New Zealand (http://www.health.govt.nz/our-work/life-stages/child-health/well-child-tamariki-ora-services/growth-charts). The overweight and obesity cut-offs for children and adolescents are the same values used in each respective growth chart, reflecting the general population cut-offs in the absence of evidence to guide CF-specific thresholds.
High risk of developing overweight or obesity Unintentional weight gain resulting in an increasing of ≥2 BMI centile bands
BMI ≥27 kg/m2 AND/OR unintentional weight gain from previously acceptable BMI of >5 kg within a year.
Diet and activity assessment, plus consideration of medical and psychosocial contributing factors. Consider goal-directed nutritional counselling
1 Source: Saxby N, Painter C, Kench A, King S, Crowder T, van der Haak N, et al. Nutrition Guidelines for Cystic Fibrosis in Australia and New Zealand. Bell S, editor. Sydney: Thoracic Society of Australia and New Zealand; 2017.
Adapted from Australian population guidelines and previous Australasian and international recommendations for CF.
WHO growth charts are used for all infants <2 years of age. For 2–18 years, at the time of writing, CDC growth charts are used in Australia, NZ-WHO growth charts are used in New Zealand (http://www.health.govt.nz/our-work/life-stages/child-health/well-child-tamariki-ora-services/growth-charts). The overweight and obesity cut-offs for children and adolescents are the same values used in each respective growth chart, reflecting the general population cut-offs in the absence of evidence to guide CF-specific thresholds.
See ‘Interpreting anthropometric measurements in children and adolescents’ in the full guideline document.
Persistent undernutrition refers to undernutrition that is non-responsive to previous recommended interventions over a period of monitoring and evaluation that is individually determined by the treating CF team.
While there are no evidence-based guidelines for treating overweight in infancy, recognition of rapid weight gain might identify if interventions to ameliorate the rate of weight gain are indicated (Centers for Disease Control, https://www.cdc.gov/mmwr/pdf/rr/rr5909.pdf). Important to distinguish between catch-up growth after early deficit, and rapid weight gain risking overweight or obesity in childhood.
The guideline classifies optimal nutritional status with the same targets as previously published for CF: BMI 50th percentile for children and adolescents / 22 kg/m2 in adult females and 23 kg/m2 in adult males [
Evidence-based practice recommendations for nutrition-related management of children and adults with cystic fibrosis and pancreatic insufficiency: results of a systematic review.
], a decline in nutritional status is recognised as a risk. This guideline augments information in existing guidelines by including additional BMI targets (percentiles or thresholds) below which nutrition intervention should be escalated from routine anticipatory guidance. A 2008 study reported both a relative lack of specific criteria used to initiate and cease both ONS and enteral nutrition, and wide variation in the criteria being used [
Evidence-based practice recommendations for nutrition-related management of children and adults with cystic fibrosis and pancreatic insufficiency: results of a systematic review.
]. Recommendations for managing undernutrition cover behavioural interventions, oral nutrition support, enteral nutrition and appetite stimulants. In this highlights paper, the topics of oral nutrition supplementation and enteral feeding were chosen to provide a sample of how the PICOs and accompanying recommendations and practice points appear in the full guideline document (Table 3).
Table 3PICOs, recommendations and practice points for Chapter 6.1 – Interventions for Undernutrition in CF.
Source: Saxby N, Painter C, Kench A, King S, Crowder T, van der Haak N, et al. Nutrition Guidelines for Cystic Fibrosis in Australia and New Zealand. Bell S, editor. Sydney: Thoracic Society of Australia and New Zealand; 2017.
Chapter 6–6.1 Undernutrition
Behaviour Modification Strategies
Q 6.1.1
Compared to standard nutritional care, do behavioural interventions around food and mealtimes improve behaviours, diet variety, and weight or nutrition status in children with CF?
R 6.1.1
GRADE B. Offer behavioural modification strategies to children at risk of/or with identified undernutrition. Conduct behavioural modification strategies in combination with nutrition education.
Q 6.1.2
When should behavioural interventions around food and mealtimes be considered for children with CF?
R 6.1.2
GRADE C. Commence behavioural modification strategies early in life (i.e. during infancy or toddlerhood) and potentially continue throughout childhood. Offer the following strategies:
•
Differential attention (praise and ignoring)
•
Contingency management (child only receives a desired reward after they have eaten their meal and/or performed desired mealtime behaviours)
•
Self-monitoring of food intake (parents and/or child)
•
Parental limit setting (establishing clear expectations and consequences)
PP 6.1.1 and 6.1.2
Behavioural modification strategies are a valuable component of standard paediatric CF care Strategies should be considered at a young age, before disruptive eating and mealtime behaviours become an ongoing issue. For best results, strategies should be conducted with nutrition education.
Enteral Feeding
Q 6.1.6
Should enteral feeding be considered to improve nutrition outcomes for people with CF?
R 6.1.6
GRADE B. Consider enteral feeding as a means of improving markers of nutritional status (including weight, BMI and BMI z-score) in children and adults with CF who have been assessed as being undernourished.
Q 6.1.7
Should enteral feeding be considered to improve pulmonary status in people with CF?
R 6.1.7
GRADE C. Practitioners should refrain from commencing supplementary enteral feeding for the sole purpose of improving or stabilizing pulmonary outcomes.
PP 6.1.6 and 6.1.7
The decision to commence either short or long term enteral nutrition support should be made by an interdisciplinary team and in consultation with the individual and their family, including discussion of risks and benefits.
•
Benefits on nutrition outcomes, particularly weight and BMI are well documented
•
There is no conclusive evidence to support beneficial effects on pulmonary function
The decision can be emotionally challenging for some people with CF. Where possible, appropriate psychosocial support should be provided and the individual's decision should be respected. An anaesthetist should be consulted prior to surgical or endoscopic gastrostomy tube insertion in people with moderate to severe CF lung disease.
Q 6.1.8
When should enteral feeding be introduced for people with CF?
R 6.1.8
Ungraded. There is insufficient evidence to make a recommendation regarding when to introduce enteral nutrition in CF. Evaluate appropriate timing on an individual basis.
PP 6.1.8
No evidence to support best timing for enteral nutrition support in CF. The following considerations should be noted in regards to timing of enteral nutrition:
•
Whilst many patients will have had a trial of oral nutritional supplements (ONS) prior to the need for enteral nutrition being assessed, there is no evidence that favours assessing the impact of ONS first, over proceeding to enteral nutrition. Evaluate whether to trial ONS prior to considering enteral nutrition on an individual basis
•
Enteral nutrition should be commenced prior to the onset of significant disease progression and FEV1 decline for more favourable nutritional outcomes
Q 6.1.9
What is the ideal enteral feeding regimen for people with CF?
R 6.1.9
Ungraded. There is insufficient literature to suggest the ideal enteral formula or regimen in the CF population. Select enteral formulas and devise enteral feeding regimens on an individual basis.
Q 6.1.10
What are the risks associated with enteral feeding in CF compared to the general population?
R 6.1.10
GRADE C. There is no evidence that people with CF are at increased risk of major complications and mortality as a result of enteral feeding. Manage minor side effects of enteral feeds, including stoma site issues and GORD, as for the general population.
see Chapter 6 in the full guideline document for additional practice points.
PICO = Population Intervention Comparator Outcome.
Q = Question.
R = Recommendation.
PP = Practice Points.
1 Source: Saxby N, Painter C, Kench A, King S, Crowder T, van der Haak N, et al. Nutrition Guidelines for Cystic Fibrosis in Australia and New Zealand. Bell S, editor. Sydney: Thoracic Society of Australia and New Zealand; 2017.
see Chapter 6 in the full guideline document for additional practice points.
Nutrition care in CF has historically been focussed on managing undernutrition. To the authors' knowledge, the Australian and NZ CF Nutrition guidelines are the first CF nutrition guidelines to include information on the identification, assessment and management of high BMI/BMI percentiles (Table 2). With newborn screening, lifetime centre-based multidisciplinary care, improved survival, the advent of genetic modulator therapies and other treatment improvements and increasing CF diagnoses later in life associated with milder mutations [
The clinical significance of overweight and obesity in CF is unclear. There is a plateau in the association between BMI and FEV1% predicted in the range traditionally defined as overweight (BMI 25–30 kg/m2 for adults) [
Evidence-based practice recommendations for nutrition-related management of children and adults with cystic fibrosis and pancreatic insufficiency: results of a systematic review.
]. To date, there are no universally accepted cut-offs for overweight or obesity (high BMI/BMI percentiles) in CF. For children and adolescents, the guideline proposes use of general population overweight and obesity criteria for children and adolescents (Table 2). For adults, the general population cut-offs to define the upper end of the healthy weight range (BMI 25 kg/m2 in adults) are unlikely to be applicable in chronic conditions such as CF which are associated with alterations in body composition including normal weight obesity, and it cannot be assumed that weight loss is predominantly fat mass loss [
]. The guidelines suggest that for adults, a BMI ≥27 kg/m2 or unintentional weight gain of >5 kg from a previously acceptable weight merits attention (Table 2). Regular monitoring of individuals with high BMI / BMI percentiles is important, and it is suggested that interventions aimed at reducing weight be instituted only after assessment of diet, body composition, physical activity and contributing medical and psychosocial factors, and be regularly monitored to ensure maintenance of lean body mass [
The Nutrition Intervention section of the guidelines provides guidance for assessing and managing individuals with high BMI, including consideration of weight history, body composition, dietary and lifestyle factors, lung function, the risk of metabolic disease and individualisation of dietary energy and macronutrient targets. Further research is needed to articulate risks associated with overweight and obesity, and to identify best practice management approaches. In the intervening period, the 2017 guidelines provide a starting framework for evaluating overweight/obesity in CF, against which practices can be measured and monitored. They are likely to have applicability in other regions of the world which are also seeing increases in overweight and obesity in CF [
3.5 Routine dietary management: energy and macronutrients, including essential fatty acids
Recommendations for energy intake in the 2017 guidelines are consistent with other guidelines, namely 110–200% of the population-based energy requirements. The inter- and intra-individual variation in energy requirements is emphasised, underscoring the importance of regular individualised assessment and monitoring of nutritional intake, status and goals. There was insufficient evidence to make CF-specific protein intake recommendations, however, guidance on an upper limit of 25% of energy intake from protein in line with recommendations for the general population is provided [
The guideline provides a comprehensive overview of the aetiology of essential fatty acid (EFA) deficiency in CF; plant and animal-based sources of EFAs; signs and symptoms of EFA deficiency; the evidence for dietary supplementation with omega-3 fatty acids in CF; safety considerations and monitoring of omega-3 fatty acid supplementation. In summary, while there is Grade C (satisfactory) evidence that dietary supplementation with omega-3 fatty acids may improve some biochemical and inflammatory indices for people with CF, such as improved fatty acid profiles, the evidence is insufficient to recommend their routine use for improving overall clinical outcomes.
3.6 Fat-soluble vitamins
The fat-soluble vitamins section of the guidelines provides information on food sources of each vitamin, aetiology of deficiency and toxicity, assessment of vitamin status, supplementation of vitamins A, D, E and K and monitoring of status [
The guidelines recommend a target for serum vitamin D of ≥50 nmol/L, if measured at the end of winter. When levels are measured at other times of the year, a target of 10-20 nmol/L higher is recommended [
]. This approach takes into account the geographic diversity of Australia and NZ, where due to distance or other factors it may not be feasible for every patient to have annual blood testing at the end of winter. This information provides a pragmatic approach for other countries if similar constraints on the season of measurement exist.
3.6.2 Supplementation of fat-soluble vitamins
There is satisfactory evidence to support the routine supplementation of vitamins K and E in individuals with CF [
]. However, evidence to support routine supplementation of vitamins A and D is lacking, favouring individualised supplementation guided by biochemical assessment and previous response to supplementation. In the absence of new guiding evidence, recommendations for vitamin A and E dosing remain unchanged from the 2006 guidelines (Table 4) [
]. At the time of guideline preparation, there were no studies investigating the optimal routine dosing of vitamin D to prevent deficiency in CF. The guideline points clinicians to recent US and European recommendations [
An update on the screening, diagnosis, management, and treatment of vitamin D deficiency in individuals with cystic fibrosis: evidence-based recommendations from the Cystic Fibrosis Foundation.
Source: Saxby N, Painter C, Kench A, King S, Crowder T, van der Haak N, et al. Nutrition Guidelines for Cystic Fibrosis in Australia and New Zealand. Bell S, editor. Sydney: Thoracic Society of Australia and New Zealand; 2017.
Age
Vitamin A (IU)
Vitamin D (IU)
Vitamin E (IU)
Vitamin K (ug)
Infants
1500–2000
400–1000
40–80
300–1000
Young Children
1500–5000
800–2000
50–150
1000–10,000
Older children
2500–5000
800–4000
150–300
1000–10,000
Adolescents and adults
2500–5000
800–4000
150–500
1000–10,000
1 Source: Saxby N, Painter C, Kench A, King S, Crowder T, van der Haak N, et al. Nutrition Guidelines for Cystic Fibrosis in Australia and New Zealand. Bell S, editor. Sydney: Thoracic Society of Australia and New Zealand; 2017.
In recent years, there has been an increase in recommended vitamin K supplementation doses in international consensus documents, based on evidence of its role in bone health [
The minerals section of the guidelines provides a comprehensive overview of those considered to be at risk of deficiency in CF: calcium, zinc, magnesium, iron and sodium. This highlights paper will focus on iron and sodium.
3.7.1 Iron
People with CF are thought to be at an increased risk of iron deficiency due to the chronic inflammatory nature of CF, potential for inadequate dietary intake, gastrointestinal co-morbidities such as malabsorption, small intestinal bacterial overgrowth or gastroesophageal reflux, haemoptysis and chronic bacterial airway colonisation [
]. The guidelines recommend annual assessment of iron status using a combination of serum iron, transferrin and ferritin, together with a marker of inflammation such as C-reactive protein [
], and feature information on interpreting biochemical markers of iron status. In the presence of inflammation or infection, serum ferritin may be falsely elevated. Therefore if CRP is high, serum iron is low but ferritin is normal, iron deficiency should not be overlooked. Measurement of soluble transferrin receptor level can assist interpretation as it is unaffected by inflammation [
]. Information on dietary targets, animal and plant-based food sources of iron, and treatment of iron deficiency, together with guidance on oral supplementation using liquid or tablet preparations, is provided. Iron infusion should be considered when oral iron is not tolerated or fails to improve iron status. There was insufficient evidence to support the contraindication of iron supplementation in those chronically colonised with Pseudomonas aeruginosa [
] and this is compounded for people living in hot and/or humid climates. The primary factor contributing to sodium deficiency is the CFTR gene defect which affects the flow of sodium and chloride ions and water in and out of cells, resulting in higher sodium and chloride losses in sweat. There is a lack of research available to guide specific individual sodium requirements for people with CF and as a result, recommendations vary in international consensus and review documents. Recommendations for sodium requirements in Australia and NZ are outlined in the 2017 guidelines: 500-1000 mg for infants, 1000-4000 mg for children and up to 6000 mg for adolescents and adults [
]. Individual requirements may vary and are best guided by signs and symptoms of sodium depletion, dietary intake, exercise level and sweat rate. A range of strategies for the administration of sodium supplementation, for example administration in apple puree, infant formula or syringing a salt solution in divided doses across the day for infants, are available in the guidelines. The guidelines provide a useful reference for other countries with areas of hot or humid climates where local CF guidelines may not exist and for clinicians in temperate climates whose patients are travelling to hot or humid climates. Strategies to meet sodium requirements are provided in the guidelines and include commercial salt supplementation, encouraging salty foods and adding salt to food and cooking.
3.8 Pancreatic enzyme replacement therapy (PERT)
The guidelines provide information on the aetiology of pancreatic insufficiency, PERT preparations available in Australia and NZ and their mechanism of action, dosing, administration with enteral feeds, the impact of genetic modulator therapies on PERT and phthalates in PERT [
]. The practice points provide advice for clinicians to consider when dosing PERT including the maximum upper limit. The guidelines give an overview of tests available to assess pancreatic function, including the three-day faecal fat balance test and the highly sensitive and specific faecal elastase-1 test. Information on the strengths and limitations of the most common tests is also provided. The guidelines acknowledge the lack of universal consensus on a single test to determine pancreatic status [
The complex nature of CF means that the response to PERT can often be suboptimal, relating to adherence, timing, type and dose of PERT, and small intestinal pH. Fig. 1 provides a flowchart for monitoring and evaluating PERT efficacy [
1 Source: Saxby N, Painter C, Kench A, King S, Crowder T, van der Haak N, et al. Nutrition Guidelines for Cystic Fibrosis in Australia and New Zealand. Bell S, editor. Sydney: Thoracic Society of Australia and New Zealand; 2017.
One of the key advances in CF care has been the introduction of CF genetic modulator therapies. These have had significant impact on the nutritional status of CF patients, resulting in improved weight status, improved pancreatic function and normalised sweat chloride [
Long-term safety and efficacy of ivacaftor in patients with cystic fibrosis who have the Gly551Asp-CFTR mutation: a phase 3, open-label extension study (PERSIST).
Safety, pharmacokinetics, and pharmacodynamics of ivacaftor in patients aged 2-5 years with cystic fibrosis and a CFTR gating mutation (KIWI): an open-label, single-arm study.
]. To the authors' knowledge, no nutrition guideline to date has provided information on the nutrition care of patients on CFTR modulator therapies. There is excellent evidence to suggest that ivacaftor therapy leads to significant improvements in weight and BMI in children over two years of age and adults. The guidelines provide insight into how genetic modulator therapies may change the nutritional needs of people with CF together with guidance for nutritional management, including weight, energy intake targets, PERT and salt.
The evidence available at the time of writing was derived largely from studies involving ivacaftor, although the principles may translate to other genetic modulator therapies. Clinicians are encouraged to proactively monitor weight patterns during genetic modulator therapy to ensure nutritional recommendations are tailored to individual needs and changing body composition. This information is relevant worldwide, and provides clinicians with practical advice for managing patients on genetic modulator therapies. Subsequent research will contribute to further understanding of the mechanisms underlying nutritional status changes and the impact of genetic modulators on related CF treatments including insulin, which in turn will guide the evolution of practice advice and future guidelines.
3.10 Complementary therapies
To our knowledge, this is the first nutrition guideline in CF to include information on complementary therapies, highlighting the interest in the area which emerged from consumer feedback at the guideline development stage. Specific complementary therapies reviewed included probiotics, garlic, glutathione, coconut oil and herbal supplements. Probiotics is an emerging area of research in CF. The guidelines provide a summary of the available evidence at the time of guideline development. While Lactobacillus genus probiotic specifically may provide some health benefits for people with CF, there is insufficient evidence to support routine or targeted supplementation in CF [
]. The guidelines include information on safety and potential adverse effects of these therapies, and recommends that clinicians encourage patients to discuss complementary and alternative therapy use with their treating teams.
3.11 Cystic fibrosis-related co-morbidities
The guidelines address key nutrition-related co-morbidities (CF-related diabetes, CF-related liver disease, gastro-oesophageal reflux; distal intestinal obstruction syndrome, bone health); and other key topics, including pregnancy, lung transplantation and colon cancer screening, outlining evidence-based recommendations and practice guidance on nutrition and dietary management [
]. The guidelines promote an interdisciplinary approach to nutrition care and provide a useful resource to support a team approach for nutrition management for CF physicians and other clinicians in specialities including gastroenterology, hepatology and endocrinology.
4. Discussion and conclusion
The ‘2017 Nutrition Guidelines for CF in Australia and NZ’ offer a number of significant points of difference from other published nutrition guidelines, such as the inclusion of information on overweight/obesity, genetic modulators and complementary therapies. While some recommendations and practice points, such as vitamin D and salt supplementation, were prepared specifically for the Australasian context, they can be generalised to other countries with a wide latitude variation and varied climate conditions. The guidelines also include valuable, up to date information on core nutrition topics, such as growth assessment, pancreatic enzyme replacement therapy, nutrition interventions, micronutrient supplementation and nutrition-related co-morbidities.
The rigorous process undertaken to develop these evidence-based recommendations and practice points, underpinned by peer review involving both consumers and local and international clinical experts, ensures the 2017 nutrition guideline content reflects the needs of the CF community. The full guideline document contains rich narrative text which summarises the evidence that informed the recommendations. Where the quality of evidence was insufficient to make graded recommendations, practice points were developed, which provide practical material to support guideline implementation. The framework used for the guidelines will allow for revision of evidence statements and upgrading of practice points into graded recommendations as additional evidence emerges. These attributes render the guidelines particularly unique in that they are an integrated resource providing both recommendations and guidance for translation into practice for CF clinicians providing nutrition care.
The guideline acknowledges gaps in the evidence base and suggests areas for future research including, but not limited to, the optimal timing and regimen for enteral feeding; management of overweight/obesity in CF; optimal supplementation of fat-soluble vitamins including the use of high dose vitamin D; long term nutritional considerations for people on genetic modulator therapies; and the use of probiotics and other complementary therapies.
To ensure the best quality nutrition care for people with CF, it is suggested that nutrition guidelines be implemented in conjunction with local standards for CF care, a number of which have been published [
], emphasising the importance of nutrition and growth monitoring as integral components of quality CF. The full guideline document contains a framework for implementation and evaluation.
In conclusion, the ‘2017 Nutrition Guidelines for Cystic Fibrosis in Australia and NZ’ provide comprehensive guidance for the management of nutrition and nutrition-related co-morbidities in CF. They complement and augment other recently published guidelines through the use of systematic appraisal of the literature which was synthesised into evidence statements; graded recommendations, and practice points guiding translation of evidence into clinical management of people with CF. The incorporation of geographic and climatic considerations for issues such as vitamin D, salt and hydration, together with the inclusion of novel topics such as the nutritional implications of genetic modulator therapies, overweight/obesity and complementary therapies renders the guidelines a valuable resource for clinicians across the international CF community.
Funding
The guideline development received partial support from the Dietitians Association of Australia, Dietitians New Zealand and the Thoracic Society of Australia and New Zealand.
Declarations of interest
Dr. King reports personal fees from Vertex Pharmaceuticals Inc., outside the submitted work.
Tory Crowder reports personal fees from Mylan Ltd., personal fees from Abbott Nutrition, outside the submitted work.
Data from this work has been presented at the following scientific meetings:
•
39th European CF conference, 8-11th June 2016, Basel, Switzerland
•
40th European CF conference, 7-10th June 2017, Seville, Spain
•
12th Australasian CF conference, 5-8th August 2017, Melbourne, Australia
•
31st North American CF Conference, 2-4th November 2017, Indianapolis, USA
•
75th Dietitians New Zealand Conference, 30th Aug – 1st Sept 2018, Auckland, New Zealand
Acknowledgements
The authors would like to acknowledge the contributions of the members of the authorship group and interdisciplinary steering committee; Jacqueline Anderson, Robyn Baird, Rebecca Baskett, Rachel Battersby, Scott Bell, Susan Biggar, Annabel Biven, Joanna Boyle, Rachael Cavanagh, Stephanie Chen, Clare Collins, Maria Craig, Melissa Demery, Kristyn Ford, Natalie Forgione, Mary Fraser, Julie Graves, Jodi Grunert, Lisa Guest, Shihab Hameed, Karen Haworth, Karen Herd, Louise Hesketh, Jenny Heyward, Donna Hickling, D. Jane Holmes-Walker, Peter Hopkins, Kelly Josh, Tamarah Katz, Saravana Kumar, Kate Luttrell, Juliette Mahero, Angela Matson, Peter Maree, Peter Middleton, Caitlin Miles, Sue Morey, Courtney Munro, Karen McKay, Sarah McKay, Mark Oliver, Chee Y. Ooi, Maeve O'Driscoll, Paul O'Neill, Liz Powell, Bernadette Prentice, Clare Rawcliffe, Phil Robinson, Nicole Sander, Kate Steinbeck, Jenna Stonestreet, Audrey Tierney, Katie Vardy, Evelyn Volders, Kirrilee Waterhouse, Linda Williams, Denise Wong See and Michelle Wood.
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An update on the screening, diagnosis, management, and treatment of vitamin D deficiency in individuals with cystic fibrosis: evidence-based recommendations from the Cystic Fibrosis Foundation.
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Safety, pharmacokinetics, and pharmacodynamics of ivacaftor in patients aged 2-5 years with cystic fibrosis and a CFTR gating mutation (KIWI): an open-label, single-arm study.
Adapted from Australian population guidelines and previous Australasian and international recommendations for CF.
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